Device for targeted feature-specific sensory therapy

ABSTRACT

A device and method that supplements sensory input, thereby providing a supplemented sensory environment, to induce plasticity within the central nervous system that effectively overcomes sensory-neural processing deficits or strengthens specific sensory-neural abilities. In one implementation, ear-level hearing devices are used to deliver therapeutic sound with specific acoustic features that serve as archetypes of stimulus features for which sensory-neural processing is compromised by a sensory-neural deficit.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/485,194, filed on Apr. 13, 2017, the entire contents of which areincorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with government support AG009524 and DC015054awarded by the National Institutes of Health. The Government has certainrights to the invention.

BACKGROUND OF THE INVENTION

Normal and effective sensory processing involves the extraction,encoding, and weighting of stimulus input in a manner that provides aninternal neural representation of stimulus features, patterns, orchanges in those features and patterns. Sensory deficits lead to weak oraltered internal neural representation of stimulus features, patterns,or changes in those features and patterns.

Early childhood sensorineural hearing loss (SNHL) is a commonneurosensory disability causing significant medical, social andfinancial hardship. The prevalence of moderate-to-profound SNHL inchildren (>40 dB) is roughly 3 in 1,000 with up to 10% have hearing lossconsidered “profound”. There are numerous causes of congenital oracquired sensorineural hearing loss including genetic factors,environmental infections or toxins and unknown causes. Beyond thethreshold deficits seen in children with SNHL, studies have also shownfunctional difficulty with development of normal speech and languageprocessing. Importantly, deficits in fundamental perceptual attributesinvolving temporal processing have been associated with impairments inspeech perception.

SUMMARY OF THE INVENTION

Previous studies have shown that early exposure to a simple augmentedacoustic environment (AAE) can limit the effects of progressive hearingloss by rescuing peripheral function, presumably though a reduction inouter hair cell (OHC) death. Only a few studies have investigated theeffects of more complex AAE. These studies built upon the informationabove showing that changes during development affect the centralauditory system.

The technology described herein overcomes such sensory deficits bychronically supplementing the sensory experience with perceptuallysalient but unobtrusive stimuli that have stimulus features that targetthe specific sensory deficit to be treated.

Accordingly, embodiments of the invention provide an ear-level hearingdevice to support active sound therapy using specific therapeutic soundsthat target specific sensory deficits and effectively overcomes thosedeficits by altering the way in which the central nervous systemencodes, processes, or weights incoming sensory information.

One unique approach with embodiments of the invention is that theinvention uses targeted therapeutics such that the treatment is designedto target specific sensory deficits through the use of archetypalstimuli that coincide with said deficits.

In one embodiment, the invention provides a system for targetedfeature-specific sensory therapy. The system comprises a hearing deviceconfigured to provide an augmented acoustic environment, determine anarchetypal stimuli associated with a specific sensory deficit, andsupplement the augmented acoustic environment with the archetypalstimuli.

In another embodiment, the invention provides a method of targetedfeature-specific sensory therapy. The method comprises providing, with ahearing device, an augmented acoustic environment; determining aperipheral function; monitoring neural response properties followingaugmented acoustic environment exposure via the hearing device;determining whether a patterned temporal augmented acoustic environmentstimulus improves neural correlates of temporal processing; and when thepatterned temporal augmented acoustic environment stimulus improvesneural correlates of temporal processing, supplementing the augmentedacoustic environment with the patterned temporal augmented acousticenvironment stimulus.

In one construction, the monitoring of the neural response propertiesincludes monitoring at least one selected from a group consisting oftuning sharpness, frequency representation, excitatory drive, andtemporal acuity.

In another construction, the determining of the peripheral functionincludes determining the peripheral function using auditory brainstemresponse thresholds and functional outer hair cell assessment.

In yet another construction, the determining whether a patternedtemporal augmented acoustic environment stimulus improves neuralcorrelates of temporal processing includes determining whether passiveexposure to the patterned temporal augmented acoustic environmentstimulus improves neural correlates of gap detection.

Other aspects of the invention will become apparent by consideration ofthe detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a graph illustrating neural correlates of gap detection wherethe 80-dB carrier level exposure to both types of AAE resulted inshorter mean MGT.

FIG. 1B is a graph illustrating neural correlates of gap detection wherethe 70-dB carrier level exposure to both types of AAE again shorten meanMGT, with greater improvement seen in the temporal AAE exposure group.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it isto be understood that the invention is not limited in its application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the following drawings.The invention is capable of other embodiments and of being practiced orof being carried out in various ways.

The invention according to some embodiments involves technology thatchronically supplements sensory input, thereby providing a supplementedsensory environment, to induce plasticity within the central nervoussystem that effectively overcomes sensory-neural processing deficits orstrengthens specific sensory-neural abilities. In one implementation ofthis technology, an ear-level hearing device is used to delivertherapeutic sound with specific acoustic features that serve asarchetypes of stimulus features for which sensory-neural processing iscompromised by a sensory-neural deficit. Use cases include but are notlimited to the following:

(1) Given a sensory processing deficit that leads to impaired temporalenvelope processing, the therapeutic technology involves generation of asound with a range of relevant temporal envelope features and chronicdelivery of this sound through the ear-level device at a presentationlevel that renders the features audible and relevant but not bothersomeor interfering with normal everyday tasks.

(2) Given a sensory processing deficit that leads to an impaired abilityto separate sounds of interest from competing sounds, the therapeutictechnology involves generation of a sound with a range of relevanttarget-background combinations and chronic delivery of this soundthrough the ear-level device at a presentation level that renders thefeatures audible and relevant but not bothersome or interfering withnormal everyday tasks.

(3) Given a sensory processing deficit that leads to impaired perceptionof fine temporal details, the therapeutic technology involves generationof a sound with a range of relevant rapid temporal patterns and chronicdelivery of this sound through the ear-level device at a presentationlevel that renders the features audible and relevant but not bothersomeor interfering with normal everyday tasks.

(4) Given a sensory processing deficit that leads to an impaired abilityto use binaural difference cues, the therapeutic technology involvesgeneration of a sound with a range of relevant interaural differencesand chronic delivery of this sound through the ear-level device at apresentation level that renders the features audible and relevant butnot bothersome or interfering with normal everyday tasks.

(5) Given a sensory processing deficit that leads to an impaired abilityto use spectral features, the therapeutic technology involves generationof a sound with a range of relevant spectral features and chronicdelivery of this sound through the ear-level device at a presentationlevel that renders the features audible and relevant but not bothersomeor interfering with normal everyday tasks.

(6) Given a sensory processing deficit that leads to an impaired abilityto encode stimulus loudness, the therapeutic technology involvesgeneration of a sound with a range of relevant intensive features andchronic delivery of this sound through the ear-level device at apresentation level that renders the features audible and relevant butnot bothersome or interfering with normal everyday tasks.

The ear-level hearing device, according to an embodiment of theinvention, may be earphones, headsets, hearing aids, cochlear implants,or the like. In one construction, the ear-level hearing device generatesthe sounds and delivers the sounds to the user. In another construction,the sound is output to a user (e.g., at 70 dB Sound Pressure Level(SPL)) from a speaker that may be positioned on a support (e.g., speakerstand, table, platform, or the like). In a further construction, thesound is output to a user via direct connection (e.g., cable, cord,link, or the like) or wirelessly via a network (e.g., Wi-Fi, Bluetooth,or the like).

Psychoacousticians have used gap detection paradigms to evaluatetemporal acuity for more than 30 years. Minimal gap threshold (MGT)correlates well to voice onset time (VOT), the interval betweenconsonant release and the start of vocal cord vibration inconsonant-vowel transitions. Temporal processing ability during childdevelopment and in adults has been linked to speech recognitionabilities and normal language development. Furthermore, gap detectioncan also be measured in animal models using several different behavioraltechniques and results indicate that nearly all mammals have similarMGTs, which are on the order of 2-3 msec. In addition, neural correlatesof gap detection have been shown to approximate behavioral measures insingle-neuron recordings from inferior colliculus (IC) neurons of youngmice.

There are several mouse models that mimic several of the different typesand progressive nature of congenital SNHL. The DBA strain, the oldestinbred mouse strain contains a mutation to the gene Cdh23, as well as anucleotide substitution in the fascin-2 gene (Fscn2), the causative geneof the Ahl8 modifier locus. This strain shows a rapid, progressive lossin peripheral function beginning at the onset of hearing and displaymany of the audiometric characteristics found in infants withprogressive sensorineural hearing loss. DBA mice have early and rapidloss of OHC function in a base to apex progression, as measured bydistortion product otoacoustic emission (DPOAE) thresholds.

Previous studies have shown that when newborn DBA mice are exposed tobroadband sounds, on a daily basis, over 12-hour cycles results inimproved peripheral and central auditory function. In addition topreserving hearing sensitivity, exposure to this augmented acousticenvironment (AAE) limits hair cell loss. In the central auditory system,AAE exposure preserves AVCN volume and neuronal cell counts, possibly bymaintaining afferent neuronal input to the auditory brainstem.Additionally, AAE exposure expands the frequency range that IC neuronsare sensitive to across the dorso-ventral axis compared to non-exposedmice. When normal-hearing, young adult CBA mice are exposed to AAE noeffects, positive or negative, are observed (Willott, Turner, & Sundin,2000). Clearly, in mouse models of congenital SNLH, AAE exposure showspromise in ameliorating the effects of rapid progressive SNHL, but itsusefulness in other auditory domains has yet to be studied.

Gap detection improved in phasic units following exposure to both typesof AAE, with greater improvement seen following exposure to a noveltemporal AAE. Representative post-stimulus time histograms (PSTHs) froma single unit in each exposure group, at different gap durations, areshown in FIGS. 1A and 1B. Mean gap thresholds (MGTs) were computedacross all responding units in each exposure group, where respondingunits are units with a gap threshold ≤96 ms. At the 80-dB carrier level(FIG. 1A), both types of AAE shorten mean MGT (one-way ANOVA, F=15.43,p<0.001). The magnitude of the improvement between regular AAE exposureand control was 4.89 ms (a 33% improvement), and between temporal AAEexposure and control was 6.58 ms (a 44% improvement). At the 70-dBcarrier level (FIG. 1B), both types of AAE exposure also improve themean MGT compared to controls (F =12.49, p<0.001), with greaterimprovement seen by mice exposed to temporal AAE (12.7±1.0 ms versus20.8±1.5 ms, p<0.001). At all levels, temporal AAE-exposed mice had thegreatest percent of phasic units with the shortest gap thresholds. Theimpact of AAE on the response to gaps by tonic units was minimal andshowed no significant effects of AAE exposure on gap thresholds (datanot shown).

Exposure to temporal AAE also preserved neural correlates of gapdetection in the presence of continuous background noise (CBN). Only asubset of phasic units were responsive in background noise. In thepresence of +6 dB SNR continuous background noise (an 80-dB SPL carrierpresented with 74-dB SPL CBN) a significant effect of exposure on MGTwas observed (one-way ANOVA: F=5.39, p=0.005). Exposure to temporal AAEsignificantly shortened MGTs compared to controls (12.7±1.0 ms versus17.9±1.2 ms, p<0.01) while exposure to regular AAE trended towardsshorter MGTs (14.6±1.2 ms versus 17.9±1.2 ms, p>0.05). Tonic unitsrecorded in continuous background noise demonstrated post-excitatorysuppression. Due to post-excitatory suppression, the quiet windowresponses of these units were not strictly a result of the embeddedsilent gap making gap detection threshold determination highly variable.This increased variability for tonic responders prevented reliabledetermination of the MGT.

As illustrated in FIGS. 1A and 1B, neural correlates of gap detectionare improved following 60 days of patterned AAE exposure. Exposure toboth types of AAE (regular and temporal) improve mean gap thresholds inphasic units. Mean gap thresholds (MGTs) were computed across eachgroup, for each noise carrier level (80, 70 & 60 dB). As seen in FIG.1A, the 80-dB carrier level exposure to both types of AAE resulted inshorter mean MGT (Control: 15.0±1.1 ms, Reg. AAE: 10.1±0.9, TemporalAAE: 8.4±0.7 ms). As seen in FIG. 1B, the 70-dB carrier level, exposureto both types of AAE again shorten mean MGT, with greater improvementseen in the temporal AAE exposure group (Control: 20.8±1.5 ms, Reg. AAE:15.7±1.0, Temporal AAE: 12.7±1.0 ms).

Various features and advantages of the invention are set forth in thefollowing claims

What is claimed is:
 1. A system for targeted feature-specific sensorytherapy, the system comprising: a hearing device configured to providean augmented acoustic environment, determine an archetypal stimuliassociated with a specific sensory deficit, and supplement the augmentedacoustic environment with the archetypal stimuli.
 2. The system of claim1, wherein the specific sensory deficit includes impaired temporalenvelop processing.
 3. The system of claim 2, wherein the hearing deviceis configured to supplement the augmented acoustic environment with thearchetypal stimuli by generating a sound with a range of relevanttemporal envelope features and chronically delivering the sound at apresentation level that renders the features audible and relevant. 4.The system of claim 1, wherein the specific sensory deficit includesimpaired ability to separate sounds of interest from competing sounds.5. The system of claim 4, wherein the hearing device is configured tosupplement the augmented acoustic environment with the archetypalstimuli by generating a sound with a range of relevant target-backgroundcombinations and chronically delivering the sound at a presentationlevel that renders the features audible and relevant.
 6. The system ofclaim 1, wherein the specific sensory deficit includes impairedperception of fine temporal details.
 7. The system of claim 6, whereinthe hearing device is configured to supplement the augmented acousticenvironment with the archetypal stimuli by generating a sound with arange of relevant rapid temporal patterns and chronically delivering thesound at a presentation level that renders the features audible andrelevant.
 8. The system of claim 1, wherein the specific sensory deficitincludes impaired ability to use binaural difference cues.
 9. The systemof claim 8, wherein the hearing device is configured to supplement theaugmented acoustic environment with the archetypal stimuli by generatinga sound with a range of relevant interaural differences and chronicallydelivering the sound at a presentation level that renders the featuresaudible and relevant.
 10. The system of claim 1, wherein the archetypalstimuli is designed to target the specific sensory deficit.
 11. Thesystem of claim 1, wherein the specific sensory deficit includesimpaired ability to use spectral features.
 12. The system of claim 12,wherein the hearing device is configured to supplement the augmentedacoustic environment with the archetypal stimuli by generating a soundwith a range of relevant spectral features and chronically deliveringthe sound at a presentation level that renders the features audible andrelevant.
 13. The system of claim 1, wherein the specific sensorydeficit includes impaired ability to encode stimulus loudness.
 14. Thesystem of claim 13, wherein the hearing device is configured tosupplement the augmented acoustic environment with the archetypalstimuli by generating a sound with a range of relevant intensivefeatures and chronically delivering the sound at a presentation levelthat renders the features audible and relevant.